Recent developments in dynamic electrochemical studies of adsorbed enzymes and their active sites.

This review outlines recent developments in electrochemical investigations of proteins adsorbed on electrodes. The important point about 'protein film voltammetry' is that it addresses the rates of reactions that occur in enzymes - catalysis, inhibition, electron flow - as a function of potential; in other words, it introduces the 'potential dimension' into enzyme kinetics. Some surprisingly subtle, yet significant observations are made, including demonstration of a special role for Mo(V) in the catalytic cycle of Mo enzymes, quantitation of the catalytic bias in multi-centred enzymes such as mitochondrial Complex I, insight into mechanisms of proton transfer in enzymes, and properties of proteins that are covalently attached directly to a gold surface.